Revamp color handling.

3 files changed, 55 insertions, 23 deletions

diff --git a/libdimension/dimension/canvas.h b/libdimension/dimension/canvas.h
index 8959e12..21d56e4 100644
--- a/libdimension/dimension/canvas.h
+++ b/libdimension/dimension/canvas.h
@@ -25,15 +25,6 @@
 #ifndef DIMENSION_CANVAS_H
 #define DIMENSION_CANVAS_H
 
-/* 48-bit sRGB color for pixels. */
-typedef struct {
-  uint16_t r, g, b; /* Red, green, blue */
-  uint16_t a, t;    /* Filtered transparancy, normal transparancy */
-} dmnsn_pixel;
-
-dmnsn_pixel dmnsn_pixel_from_color(dmnsn_color color);
-dmnsn_color dmnsn_color_from_pixel(dmnsn_pixel pixel);
-
 typedef struct {
   unsigned int x, y;
 
@@ -41,7 +32,7 @@ typedef struct {
    * Stored in first-quadrant representation (origin is bottom-left).  The pixel
    * at (a,b) is accessible as pixels[b*x + a].
    */
-  dmnsn_pixel *pixels;
+  dmnsn_color *pixels;
 } dmnsn_canvas;
 
 dmnsn_canvas *dmnsn_new_canvas(unsigned int x, unsigned int y);
diff --git a/libdimension/dimension/color.h b/libdimension/dimension/color.h
index 34668e3..d637a81 100644
--- a/libdimension/dimension/color.h
+++ b/libdimension/dimension/color.h
@@ -29,16 +29,57 @@
 extern "C" {
 #endif
 
-/* CIE 1931 xyY color. */
+/* Internally, we use CIE 1931 XYZ color. */
+typedef struct {
+  double X, Y, Z;
+  double filter, trans; /* Filter transparancy only lets light of this color
+                           through; regular transparancy lets all colors
+                           through.  filter + trans should be <= 1.0. */
+} dmnsn_color;
+
+typedef struct {
+  double X, Y, Z; /* X, Y, and Z are tristimulus values, unbounded above zero.
+                     Diffuse white is (0.9505, 1, 1.089). */
+} dmnsn_CIE_XYZ;
+
 typedef struct {
   double x, y, Y; /* x and y are chromaticity coordinates, and Y is luminance,
                      in the CIE 1931 xyZ color space.  We use an unlimited light
                      model, so x,y in [0, 1] and Y >= 0, with 1 = diffuse
                      white */
-  double filter, trans; /* Filter transparancy only lets light of this color
-                           through; regular transparancy lets all colors
-                           through */
-} dmnsn_color;
+} dmnsn_CIE_xyY;
+
+typedef struct {
+  double L, a, b; /* L is luminence (100 = diffuse white); a and b are color-
+                     opponent dimensions.  This color space is used for color
+                     arithmetic. */
+} dmnsn_CIE_Lab;
+
+typedef struct {
+  double L, u, v; /* L is luminence (100 = diffuse white); u and v are
+                     chromaticity coordinates. */
+} dmnsn_CIE_Luv;
+
+typedef struct {
+  double R, G, B; /* sRGB R, G, and B values */
+} dmnsn_sRGB;
+
+/* Standard whitepoint, determined by the conversion of sRGB white to XYZ */
+extern dmnsn_CIE_XYZ whitepoint;
+
+dmnsn_color dmnsn_color_from_XYZ(dmnsn_CIE_XYZ XYZ);
+dmnsn_color dmnsn_color_from_xyY(dmnsn_CIE_xyY xyY);
+dmnsn_color dmnsn_color_from_Lab(dmnsn_CIE_Lab Lab, dmnsn_CIE_XYZ white);
+dmnsn_color dmnsn_color_from_Luv(dmnsn_CIE_Luv Luv, dmnsn_CIE_XYZ white);
+dmnsn_color dmnsn_color_from_sRGB(dmnsn_sRGB sRGB);
+
+dmnsn_CIE_XYZ dmnsn_XYZ_from_color(dmnsn_color color);
+dmnsn_CIE_xyY dmnsn_xyY_from_color(dmnsn_color color);
+dmnsn_CIE_Lab dmnsn_Lab_from_color(dmnsn_color color, dmnsn_CIE_XYZ white);
+dmnsn_CIE_Luv dmnsn_Luv_from_color(dmnsn_color color, dmnsn_CIE_XYZ white);
+dmnsn_sRGB    dmnsn_sRGB_from_color(dmnsn_color color);
+
+dmnsn_color dmnsn_color_add(dmnsn_color color1, dmnsn_color color2);
 
 #ifdef __cplusplus
 }
diff --git a/libdimension/dimension/geometry.h b/libdimension/dimension/geometry.h
index 2c0c204..11a6daf 100644
--- a/libdimension/dimension/geometry.h
+++ b/libdimension/dimension/geometry.h
@@ -31,44 +31,44 @@ typedef struct { dmnsn_scalar x, y, z; } dmnsn_vector;
 
 /* Vector arithmetic */
 
-inline dmnsn_vector
+DMNSN_INLINE dmnsn_vector
 dmnsn_vector_construct(dmnsn_scalar x, dmnsn_scalar y, dmnsn_scalar z)
 {
   dmnsn_vector v = { .x = x, .y = y, .z = z };
   return v;
 }
 
-inline dmnsn_vector
+DMNSN_INLINE dmnsn_vector
 dmnsn_vector_add(dmnsn_vector lhs, dmnsn_vector rhs)
 {
   return dmnsn_vector_construct(lhs.x + rhs.x, lhs.y + rhs.y, lhs.z + rhs.z);
 }
 
-inline dmnsn_vector
+DMNSN_INLINE dmnsn_vector
 dmnsn_vector_sub(dmnsn_vector lhs, dmnsn_vector rhs)
 {
   return dmnsn_vector_construct(lhs.x - rhs.x, lhs.y - rhs.y, lhs.z - rhs.z);
 }
 
-inline dmnsn_vector
+DMNSN_INLINE dmnsn_vector
 dmnsn_vector_mul(dmnsn_scalar lhs, dmnsn_vector rhs)
 {
   return dmnsn_vector_construct(lhs*rhs.x, lhs*rhs.y, lhs*rhs.z);
 }
 
-inline dmnsn_vector
+DMNSN_INLINE dmnsn_vector
 dmnsn_vector_div(dmnsn_vector lhs, dmnsn_scalar rhs)
 {
   return dmnsn_vector_construct(lhs.x/rhs, lhs.y/rhs, lhs.z/rhs);
 }
 
-inline dmnsn_scalar
+DMNSN_INLINE dmnsn_scalar
 dmnsn_vector_dot(dmnsn_vector lhs, dmnsn_vector rhs)
 {
   return lhs.x*rhs.x + lhs.y*rhs.y + lhs.z*rhs.z;
 }
 
-inline dmnsn_vector
+DMNSN_INLINE dmnsn_vector
 dmnsn_vector_cross(dmnsn_vector lhs, dmnsn_vector rhs)
 {
   return dmnsn_vector_construct(lhs.y*rhs.z - lhs.z*rhs.y,
@@ -83,7 +83,7 @@ typedef struct {
 } dmnsn_line;
 
 /* A point on a line, defined by x0 + t*n */
-inline dmnsn_vector
+DMNSN_INLINE dmnsn_vector
 dmnsn_line_point(dmnsn_line l, dmnsn_scalar t)
 {
   return dmnsn_vector_add(l.x0, dmnsn_vector_mul(t, l.n));